Expert systems are computer systems that are used to store large amounts of information on a particular topic in a computer database and are designed to respond to queries from a user to provide information about a particular problem. For example, there are expert systems that are used to guide boats through a harbor. Such an expert system contains information in a database that relates to the heights of bridges and the depths of channels in the harbor. A user can query this system on what route it should take with a boat having certain dimensions.
One drawback of these expert systems is that if a user's query asks for information not contained in the data base specifically about that subject, the expert system cannot provide any information. It cannot create ideas and it cannot solve problems by analogy.